Risk Factors Associated With the Absence of CMV-specific Cellular Immune Response in the Early Post-transplant Period in Low-risk CMV-seropositive Kidney Transplant Recipients

Overview

The goal of this observational study is to identify risk factors associated with the absence of CMV-specific cellular immune response in low-risk CMV-seropositive kidney transplant recipients in the early post-transplant period. The participant population includes adult CMV-seropositive kidney transplant recipients who did not receive antithymocyte globulin (ATG) induction therapy and underwent QuantiFERON-CMV testing within the first 45 days after transplantation. The main question it aims to answer is: \- Is it possible to predict which patients will fail to develop a CMV-specific cellular immune response before day 45 post-transplant in the absence of directly available immune assessment techniques? Researchers will compare patients with reactive QuantiFERON-CMV results to patients with non-reactive or indeterminate results to identify factors associated with the absence of CMV-specific cellular immune response. Participants will have retrospective clinical and laboratory data collected from medical records.

Study Hypothesis: In the absence of available techniques to assess CMV-specific cellular immunity, it may be possible to predict which patients will fail to develop a CMV-specific cellular immune response before day 45 post-transplant. Objective: Primary objective: * Derivation Cohort: To evaluate the risk factors associated with a non-reactive or indeterminate QF-CMV result before day 45 post-transplant in CMV-seropositive (R⁺) recipients who did not receive ATG prophylaxis. * Validation Cohort: To validate these risk factors in an independent validation cohort. Secondary Objectives: * To confirm whether patients with a non-reactive or indeterminate QF-CMV result before day 45 post-transplant and without ATG induction develop a higher rate of clinically significant CMV infection compared with those with a reactive QF-CMV result during the first 6 months post-transplant. * To confirm whether these same patients present a higher rate of viral replication during the first 6 months post-transplant. Study Population: The study will include adult patients (\>18 years) who are CMV-seropositive (R⁺), received a kidney transplant during the study period, did not receive ATG prophylaxis, and underwent QF-CMV testing on day 45 post-transplant (with a window period between day 30 and day 60 post-transplant).